5 folders cost $4.80. Which equation would help determine the cost of 7 folders?
Explanation: There are several equations that could help determine the cost, each with a slightly different approach. If we let $x$ represent the cost of 7 folders, we have the following proportion: $\dfrac{x}{7}$ We have to pay $4.80 for 5 folders, and that can be written as a proportion: $\dfrac{\$4.80}{5}$ Since the price per folder stays the same, these two proportions are equivalent. $\dfrac{x}{7} = \dfrac{\$4.80}{5}$